Effective strategies for reclamation of saline-alkali soil and response mechanisms of the soil-plant system

• Published in: The Science of the total environment Vol. 905; p. 167179
• Main Authors: Xu, Xin, Guo, Lin, Wang, Shaobo, Wang, Xuanyi, Ren, Meng, Zhao, Pengjie, Huang, Ziyi, Jia, Hongjun, Wang, Jinhang, Lin, Aijun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.12.2023
• Subjects: bentonite; Brassica napus; carboxymethylcellulose; catalase; community structure; edaphic factors; equations; humic acids; nutrient content; peroxidase; phosphogypsum; Plant growth; proline; reactive oxygen species; Remediation; Response mechanism; Saline-alkali soil; salt content; salt stress; soil; soil microorganisms; soil nutrients; Soil quality; soil restoration; soil salts; sugars; superoxide dismutase; Soil quality; Remediation; Plant growth; Response mechanism; Saline-alkali soil
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.167179

The combination of amendments has emerged as a potential strategy to efficiently alleviate salt stress in saline-alkali soil. However, knowledge regarding how to optimize the proportion of different amendment materials, comprehensively assess the contribution of each component, and clarify the response mechanisms of the amendment-saline-alkali soil-plant system is incomplete. Based on this, we conducted a pot experiment to evaluate the improvement effect of the combined application of different amendment materials at varying levels and the contribution of the amendment components to alleviating salt stress. Overall, T6 exhibited the most significant improvement effect on the physicochemical and biological properties of the saline-alkali soil and promoted the growth of oilseed rape, with the levels of 2.0 % phosphogypsum, 2.0 % humic acid, 0.25 % bentonite, and 0.03 % sodium carboxymethyl cellulose. Compared with the control group, the EC decreased by 1.51 % to 33.49 %, the soil salt content dropped by 11.40 % to 35.46 %, and the soil soluble Na + concentration significantly declined by 39.47 % to 63.20 %. Additionally, the soil nutrient content and soil microbial community structure were enhanced in treatment groups. Meanwhile, amendments alleviated salt stress in the oilseed rape plant by activating anti-oxidative enzymes and osmoregulatory substances such as soluble sugar and proline, thus improving their ability to remove reactive oxygen species (ROS). The anti-oxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly increased, with an increase of 10.68 % (SOD, T2) ∼207.31 % (CAT, T6) compared to the control group. The structural equation modeling (SEM) analysis and simulation experiments indicated that the amendment components synergically promoted the amelioration effect on salt stress, and effectively improved soil properties, which affected the response of oilseed rape to soil environment. This research paper provides the relevant reference for the combined application of different amendment materials for soil reclamation. [Display omitted] •T6 had optimal proportion of each component and the significant improvement effect.•The salt content of soil decreased by 11.40–35.46 % after the amendment was applied.•Plants relied on antioxidant enzymes and osmoregulatory factors to resist salt stress.•The components of the amendment synergically improved soil environment and plants.